When resinous wood species are used in pulping processes, particularly mechanical pulping processes, pitch problems arise. This widespread phenomenon causes production intermptions and a decreased paper product quality.
Pitch contains considerable amounts of triglycerides, more commonly known as fats, and other esters. Faty acid glyceride hydrolysing enzymes, in the following called lipases, may advantageously be used for efficient hydrolysis of water-insoluble esters, particularly triglycerides.
In order to comply with the prerequisite for paper pulp processing, lipases applied in methods for enzymatic pitch control should be acidophilic and thermophilic.
Enzymes suggested in the prior art for pitch control include lipases derived from strains of Pseudomonas, Humicola, Candida, Chromobacter and Aspergillus.
Some of these lipases are markedly thermophilic, others are markedly acidophilic, but none of these lipases possess both characteristics.
Hyphozyma is a nlew genus of yeast-like Hyphomycetes (vide de Hoog, G. S. & Smith, M.Th.; Antonie van Leeuwenhoek 47 (1981) 339-352), and the following species are reported: H. vanabilis, M. variabilis var. odora, H. sanguinea, and H. roseoniger. However, no lipase production has previously been ascribed to these organsms.